Separator for electrochemical cell

ABSTRACT

An electrochemical cell having one or more electrodes with TMCCC materials introduces improved performance by including a special separator having ceramics and/or a discrete multilayer construction. TMCCC materials with no surface modifications, and existing electrolytes with no composition modifications are combined with a different grade of separator to improve cell performance.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of application Ser. No. 17/650,178filed on Feb. 7, 2022, the contents of which are hereby expresslyincorporated by reference thereto in its entirety for all purposes.

FIELD OF THE INVENTION

The present invention relates generally to electrochemical cellsincluding a coordination compound electrochemically active in one ormore electrodes, and more specifically, but not exclusively, for examplewherein one or more electrodes include one or more transition metalcyanide coordination compounds; and even more specifically, but notexclusively, to an improvement in such an electrochemical cell,including a separator material having one or more ceramic species.

BACKGROUND OF THE INVENTION

The subject matter discussed in the background section should not beassumed to be prior art merely as a result of its mention in thebackground section. Similarly, a problem mentioned in the backgroundsection or associated with the subject matter of the background sectionshould not be assumed to have been previously recognized in the priorart. The subject matter in the background section merely representsdifferent approaches, which in and of themselves may also be inventions.

Electrochemical cells may include transition metal cyanide coordinationcompound (TMCCC) electrode materials and porous separators that act as abarrier to an electric short circuit between the two electrodes of thecell. Less well-described is the composition of matter of theseseparators used with TMCCC-containing electrodes. TMCCC electrodematerials and other electrode materials are known to have degradationmodes including (but not limited to) release of chemical species intothe cell's liquid electrolyte, such as dissolved transition metalcations, or water, or other species. Possible solutions to theseproblems include modifications of the surface of those electrodematerials with protective coatings, as well as modifications to thecomposition of liquid electrolytes to suppress release of such chemicalspecies. Surface coating may limit charge transfer, and therefore chargeand discharge rates. Similarly, electrolyte compositions that suppressrelease of chemical species may not have other properties desirable forhigh cell performance, such as high ionic conductivity or low viscosity.

Electrochemical cells are designed such that two electrodes areseparated by a separator that electronically insulates the twoelectrodes while also being ionically conductive to allow ions todiffuse between the electrodes and participate in electrochemicalreactions. An example of such an electrochemical cell is a lithium-ioncell. Common separator materials used in the lithium-ion chemistryinclude polyolefin membranes that may or may not contain ceramicspecies. The separator plays a key role in the electrochemical cell, andits characteristics can impact cell performance in various ways.Examples of how separator characteristics may impact cell performanceare outlined in the following paragraphs.

Physical properties such as the thickness of the separator used in anelectrochemical cell can affect the nature of a pathway that ions musttravel from one electrode to the other. This in turn can influenceoverall cell impedance and therefore affect a cell's rate capability. Itis well known in the lithium-ion battery community that the thermalproperties of the separator can influence the reliability of a separatorto electronically insulate the two electrodes in an electrochemicalcell, and this is important to maintain safe operation of a cell. Forexample, when the separator readily shrinks or melts upon exposure toheat, electronic insulation between the two electrodes may be lost,causing a short-circuit event, which can lead to thermal runaway andfinally to dangerous and costly fire events.

A common way to ameliorate this safety risk is to have a three-layeredpolyolefin separator, where the inner layer is made with polyethyleneand the outer layers are made of polypropylene. In the event ofsufficient heat exposure, the polyethylene will melt and close its poresto block both ionic and electrical contact between the energizedelectrodes. At the same time, the polypropylene layers, which have ahigher melting temperature than polyethylene, will maintain theirdimensional stability and prevent the entire separator layer fromsignificant shrinking or melting. In the context of a lithium-ion cell,some separators may contain ceramic species which are more dimensionallystable under a wider temperature range, and can be favorable forimproving reliable safe operation. This is attributed to a higherthermal capacity of those ceramic species when compared to polyolefinmaterials.

A favorable separator has a composition that is chemically andelectrochemically compatible with the chemistry of the electrochemicalcell. For example, a separator that contains ceramic species may have anon-zero water content due to the hygroscopic nature of ceramicmaterials. When not dried properly, a separator may introduce water intothe electrochemical cell; the water can then participate in parasiticreactions in the electrochemical cell, such as electrolyticdecomposition of water into hydrogen and oxygen, thereby causing cellperformance loss. As such, the chemical composition and physicalproperties of the separator can influence electrochemical cellimpedance, safe operation of the cell, and the rate of cell performanceloss.

A separator may influence the electrochemical cell characteristics indifferent ways depending on the specific chemistry within theelectrochemical cell. As such, it is important to consider the effectsof separator characteristics on battery cell performance for each uniquecell chemistry. In other words, the elements of an electrochemical cell,such as any separator, are strongly influenced by the other components.A separator that is optimized in a context of a lithium-ion orsodium-ion electrochemical cell may be inappropriate or ineffective and,in extreme cases, detrimental or dangerous for use in an electrochemicalcell employing electrodes containing TMCCC materials.

Some materials used as an electrode in an electrochemical cell mayinclude TMCCC-containing components which have differentcharacteristics, affinities, considerations, and strengths requiringdifferent separator materials and construction than used in otherelectrochemistry.

Discussions of a structure and arrangement of electrochemical cellsoften do not detail any preferred or specific composition for aseparator, particularly in combination with TMCCC-containing electrodes.Details, when present, may include generalized discussions of“polymeric, gel, or solid” or “polyethylene, polypropylene, or highmelting temperature” separators in a context of electrochemical cellsincluding TMCCC-containing electrodes.

In other contexts, the state of the art may fail to appreciate anyparticular advantage or concern regarding separator materials andcompositions. It is not uncommon for some discussions to assert that nospecial restriction or consideration is applicable to selection of aseparator, particularly for non-TMCCC-containing (e.g., sodium-ion)electrodes and that any known porous separator with electrochemical andchemical stability would be appropriate. Without an appreciation of arange of considerations unique to each electrochemistry model,discussions in the context of non-TMCCC-containing electrodes usingseparators for a different electrochemistry suggest that certain viablecompositions for a separator may be undesirable or unworkable whenapplied to TMCCC-containing electrodes and electrochemistry even whileextolling advantages in a context of a non-TMCCC-containingelectrochemical cell. This reflects the unpredictable nature of thespecial combinations and permutations of the materials and structuresthat are available across the entire range of secondary electrochemicalcells. It is uncertain and unpredictable how an isolated feature fromone type of electrochemical cell will interact with other components ofan electrochemical cell employing a different electrochemistry.

Separator Considerations:

Thinner separators generally result in lower internal resistance for anelectrochemical cell, and therefore may realize a higher energyefficiency and power, as well as providing a higher energy density. Athinner separator may pose a quality and safety hazard because very thinseparators may have manufacturing defects (e.g., holes) that results ina short circuiting of two electrodes.

In contrast, thicker separators generally result in higher resistance,lower efficiency and power, and in lower energy density. They have anadvantage is that they are generally considered safer because of areduced risk of any short circuiting of the electrodes.

A porosity of a separator is the fraction of its total volume comprisedby its pores, rather than solid matter. More pore volume means morevolume for the liquid electrolyte, which correlates with higher ionicconductivity through the separator. The pores themselves may presentpaths through the separator that are relatively linear, or the path maybe quite branching and tortuous. As the path becomes more tortuous, theresulting tortuosity of the pore-defined path may also impact the ionicconductivity through the separator.

Conversely, when a chemical species at one electrode could diffuse tothe other electrode and cause a harmful chemical reaction, more tortuouspores and/or a lower pore volume (and a greater thickness) wouldpotentially delay or suppress that harmful reaction.

A composition of the separator is important for several reasonsincluding that the separator be chemically compatible with othercomponents of the electrochemical cell. For example, a polymer componentof the separator should not dissolve in the electrolyte solvents. Whenthe electrochemical cell performance is sensitive to moisture, it may bedesirable that the separator be dry, or in some cases, have an abilityto absorb water from other components of the electrochemical cell.Furthermore, the separator may desirably have thermally stability andnot undergo chemical reactions or mechanical changes when theelectrochemical cell heats up.

For electrochemical cells containing TMCCC electrodes in particular, anamount of water in the cell may have a surprisingly strong impact oncell performance. In this context, a cell that combines a TMCCCelectrode with a separator that is either extremely dry or evenhygroscopic (able to absorb water) is potentially desirable, as long asother conditions are satisfied.

Generally speaking, ceramic materials such as alumina (Al₂O₃), silica(SiO₂), or hydroxides or oxyhydroxides of either aluminum or silicon areused in separators to enhance their thermal stability. A generalconsideration is that many polymers shrink when heated, so a purelypolymer separator might shrink as the cell heats up, resulting in adangerous short circuit. Instead, these ceramics are thermally stableand do not deform mechanically with heating, so their presence isbelieved to help prevent a short circuit by providing structuralstability.

Surprisingly, use of a set of ceramic components in a separator serves adifferent purpose in combination with an electrochemical cell includinga TMCCC-containing electrode, with inclusion of ceramic components in aseparator as described herein results in an increase in the cycle life.These unexpected and useful features have been demonstrated to bereproducible as evidenced herein, offering advantages that have not beenpreviously described or suggested.

What may be beneficial is a system and method for improving performanceof an electrochemical cell having one or more electrodes with TMCCCmaterials by including a separator having ceramics.

BRIEF SUMMARY OF THE INVENTION

Disclosed is a system and method for improving performance of anelectrochemical cell having one or more electrodes with TMCCC materialsby including a special separator having ceramics and/or a discretemultilayer construction. The following summary of the invention isprovided to facilitate an understanding of some of the technicalfeatures related to managing water content of electrolytes and ofelectrodes including TMCCC materials, and is not intended to be a fulldescription of the present invention. A full appreciation of the variousaspects of the invention can be gained by taking the entirespecification, claims, drawings, and abstract as a whole. The presentinvention is applicable to other electrochemically active coordinationcompounds in addition to TMCCC materials.

An embodiment offers a novel solution by which existing TMCCC materialswith no surface modifications, and existing electrolytes with nocomposition modifications are combined with a different grade ofseparator to improve cell performance.

Embodiments of the present invention may involve a combination of known,commercially available grades of porous separators with new TMCCCelectrode material and electrolyte compositions so that the desirableperformance characteristics of those electrodes and electrolytes may bebetter optimized. For example, selection of a separator grade having theproper physical design and chemical composition may result in asignificant extension of the cycle calendar life of the electrochemicalcell, which is desirable for applications requiring repeated use (chargeand discharge) of the cell.

An embodiment of the present invention includes a secondaryelectrochemical cell having one or more TMCCC electrodes with: (a) aseparator that has a composition including a ceramic component; (b) aseparator that has a design including discrete layers of polymers andceramic components; (c) a separator having a ceramic component thatincludes nanoparticles (<100 nm in size); and/or (d) a separator havinga ceramic component that includes more than a certain mass loading (massper area) such as more than 1 g per square meter.

An embodiment includes an electrochemical cell, including a firstelectrode; a second electrode; a liquid electrolyte disposed inelectrochemical communication with the electrodes; and a separatordisposed in the liquid electrolyte and between the electrodes, theseparator including a ceramic composition; wherein one of the electrodesincludes a coordination compound.

A further embodiment includes the electrochemical cell wherein theceramic composition includes a material identifying as M_(x)O_(y)H_(x),with x, y, z identifying quantities of a metal (M), oxygen (O), andhydrogen (H). A still further embodiment includes the electrochemicalcell wherein M includes at least one of aluminum or silicon.

Another embodiment for the electrochemical cell wherein the coordinationcompound includes a transition metal cyanide coordination compoundidentified by Formula I, by AaPb[R(CN)6]c(H2O)n wherein wherein Aidentifies as one or more alkali cations and P and R each represent oneor more divalent or trivalent transition metal cations; wherein 0.5<c<1;wherein a, b, and c are related based on electrical neutrality, a >0,b>0, c>0; and wherein n=6*(1−z)+d, and wherein n>0; wherein 6*(1−z)identifies as a quantity of lattice bound water and d identifies as aquantity of non-coordinated water; wherein d≥0; wherein 0≤a≤2, and b=1.

An embodiment for an electrochemical cell includes a first electrode; asecond electrode; a liquid electrolyte disposed in electrochemicalcommunication with said electrodes; and a separator disposed in saidliquid electrolyte and between said electrodes, said separator includinga ceramic composition; wherein one of said electrodes includes acoordination compound. This electrochemical cell may include a ceramiccomposition having a material identifying as M_(x)O_(y)H_(z), with x, y,z identifying quantities of a metal (M), oxygen (O), and hydrogen (H).This electrochemical cell may include M having at least one of aluminumor silicon. One or more of these ceramic composition embodiments mayinclude ceramic particles having sizes <100 nm and/or provide aseparator having two or more discrete layers, including a first layerconsisting essentially of one or more polymers, and a second layerconsisting essentially of a ceramic composition.

Another embodiment for an electrochemical cell, includes a firstelectrode; a second electrode; a liquid electrolyte disposed inelectrochemical communication with said electrodes; and a separatordisposed in said liquid electrolyte and between said electrodes, saidseparator including a multilayer construction; wherein one of saidelectrodes includes a coordination compound.

An embodiment may provide a method for manufacturing an electrochemicalcell, including producing a first electrode including a coordinationcompound; producing a second electrode; producing a liquid electrolyte;producing a separator, said separator including a ceramic composition;and assembling the electrochemical cell including electrochemicallycommunicating said electrodes to said liquid electrolyte and disposingsaid separator between said electrodes.

Another embodiment may provide a method for manufacturing anelectrochemical cell, including producing a first electrode including acoordination compound; producing a second electrode; producing a liquidelectrolyte; producing a separator, said separator including a discretemultilayer composition; and assembling the electrochemical cellincluding electrochemically communicating said electrodes to said liquidelectrolyte and disposing said separator between said electrodes.

An embodiment includes a separator configured for use with one or moreTMCCC-containing electrodes in a secondary electrochemical cell. Thisseparator includes a set of features, including one or more of ceramicsand/or a special multilayer construction.

Any of the embodiments described herein may be used alone or togetherwith one another in any combination. Inventions encompassed within thisspecification may also include embodiments that are only partiallymentioned or alluded to or are not mentioned or alluded to at all inthis brief summary or in the abstract. Although various embodiments ofthe invention may have been motivated by various deficiencies with theprior art, which may be discussed or alluded to in one or more places inthe specification, the embodiments of the invention do not necessarilyaddress any of these deficiencies. In other words, different embodimentsof the invention may address different deficiencies that may bediscussed in the specification. Some embodiments may only partiallyaddress some deficiencies or just one deficiency that may be discussedin the specification, and some embodiments may not address any of thesedeficiencies.

Other features, benefits, and advantages of the present invention willbe apparent upon a review of the present disclosure, including thespecification, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, in which like reference numerals refer toidentical or functionally-similar elements throughout the separate viewsand which are incorporated in and form a part of the specification,further illustrate the present invention and, together with the detaileddescription of the invention, serve to explain the principles of thepresent invention.

FIG. 1 illustrates a scanning electron microscopy (SEM) image of awet-processed polyethylene separator surface;

FIG. 2 illustrates an SEM image of a dry-processed polypropyleneseparator surface;

FIG. 3 illustrates an SEM image of a surface of a first alumina-coatedseparator;

FIG. 4 illustrates an SEM image of a surface of a second alumina-coatedseparator;

FIG. 5 illustrates a constant-current charge-discharge voltage profile;

FIG. 6 illustrates a lifetime effect of base film porosity;

FIG. 7 illustrates a lifetime effect of ceramic coating;

FIG. 8 illustrates a lifetime effect of ceramic loading;

FIG. 9 illustrates a lifetime effect of ceramic species;

FIG. 10 illustrates a lifetime effect of ceramic particle size; and

FIG. 11 illustrates a generic electrochemical cell.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention provide a system and methodoptimizing electrochemical cell manufacturing by reducingcommercialization costs, including reduction of electrolyte costs usedin their manufacturing. The following description is presented to enableone of ordinary skill in the art to make and use the invention and isprovided in the context of a patent application and its requirements.

Various modifications to the preferred embodiment and the genericprinciples and features described herein will be readily apparent tothose skilled in the art. Thus, the present invention is not intended tobe limited to the embodiment shown but is to be accorded the widestscope consistent with the principles and features described herein.

Definitions

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this general inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

The following definitions apply to some of the aspects described withrespect to certain embodiments of the invention. These definitions maylikewise be expanded upon herein.

As used herein, the term “or” includes “and/or” and the term “and/or”includes any and all combinations of one or more of the associatedlisted items. Expressions such as “at least one of,” when preceding alist of elements, modify the entire list of elements and do not modifythe individual elements of the list.

As used herein, the singular terms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to an object can include multiple objects unless thecontext clearly dictates otherwise.

Also, as used in the description herein and throughout the claims thatfollow, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise. It will be understood that when an elementis referred to as being “on” another element, it can be directly on theother element or intervening elements may be present therebetween. Incontrast, when an element is referred to as being “directly on” anotherelement, there are no intervening elements present.

As used herein, the term “set” refers to a collection of one or moreobjects. Thus, for example, a set of objects can include a single objector multiple objects. Objects of a set also can be referred to as membersof the set. Objects of a set can be the same or different. In someinstances, objects of a set can share one or more common properties.

As used herein, the term “adjacent” refers to being near or adjoining.Adjacent objects can be spaced apart from one another or can be inactual or direct contact with one another. In some instances, adjacentobjects can be coupled to one another or can be formed integrally withone another.

As used herein, the terms “connect,” “connected,” and “connecting” referto a direct attachment or link. Connected objects have no or nosubstantial intermediary object or set of objects, as the contextindicates.

As used herein, the terms “couple,” “coupled,” and “coupling” refer toan operational connection or linking. Coupled objects can be directlyconnected to one another or can be indirectly connected to one another,such as via an intermediary set of objects.

The use of the term “about” applies to all numeric values, whether ornot explicitly indicated. This term generally refers to a range ofnumbers that one of ordinary skill in the art would consider as areasonable amount of deviation to the recited numeric values (i.e.,having the equivalent function or result). For example, this term can beconstrued as including a deviation of ±10 percent of the given numericvalue provided such a deviation does not alter the end function orresult of the value. Therefore, a value of about 1% can be construed tobe a range from 0.9% to 1.1%.

As used herein, the terms “substantially” and “substantial” refer to aconsiderable degree or extent. When used in conjunction with an event orcircumstance, the terms can refer to instances in which the event orcircumstance occurs precisely as well as instances in which the event orcircumstance occurs to a close approximation, such as accounting fortypical tolerance levels or variability of the embodiments describedherein.

As used herein, the terms “optional” and “optionally” mean that thesubsequently described event or circumstance may or may not occur andthat the description includes instances where the event or circumstanceoccurs and instances in which it does not.

As used herein, the term “size” refers to a characteristic dimension ofan object. Thus, for example, a size of an object that is spherical canrefer to a diameter of the object. In the case of an object that isnon-spherical, a size of the non-spherical object can refer to adiameter of a corresponding spherical object, where the correspondingspherical object exhibits or has a particular set of derivable ormeasurable properties that are substantially the same as those of thenon-spherical object. Thus, for example, a size of a non-sphericalobject can refer to a diameter of a corresponding spherical object thatexhibits light scattering or other properties that are substantially thesame as those of the non-spherical object. Alternatively, or inconjunction, a size of a non-spherical object can refer to an average ofvarious orthogonal dimensions of the object. Thus, for example, a sizeof an object that is a spheroidal can refer to an average of a majoraxis and a minor axis of the object.

When referring to a set of objects as having a particular size, it iscontemplated that the objects can have a distribution of sizes aroundthe particular size. Thus, as used herein, a size of a set of objectscan refer to a typical size of a distribution of sizes, such as anaverage size, a median size, or a peak size.

As used herein, the term “coordination compound” includes a materialincluding one or more coordination complexes.

As used herein, the term “residual water content” of a coordinationcompound, particularly a TMCCC material, refers to a total water contentof the TMCCC. Residual water content includes a total water mass dividedby a total dry mass of the TMCCC material (the mass of the metals, CNgroups, and any other chemical species such as chelating species). Forexample, in the case of a TMCCC with a dry mass of 100 g and a totalwater content of 10 g, then the residual water content is calculated as10 g water/100 g dry mass=10%.

As used herein, a water content of a class of coordination compoundmaterials is a complex topic and refers to a hybrid residual water statewhich identifies a coordinated water content (e.g., coordinated water)and a non-coordinated water content (e.g., non-coordinated water).Non-coordinated water may be present in various ways, primarily asinterstitial water and/or water bound to surfaces of particles of thecoordination compound materials and/or water present in any pores ormicropores within a TMCCC particle. As used herein, “coordinated water”is meant as an abbreviated term for “transition metal-coordinated water”and, as such, specifically describes water molecules that coordinate totransition metal atoms, and not to alkali metal ions. While theinteraction between water and alkali metal ions could generally also beunderstood as “coordinated”, water molecules that interact with alkaliions and not with transition metal atoms are considered herein, due totheir relatively weak interaction, as belonging to the category ofnon-coordinated water. Coordinated water molecules are strongly bound totransition metal atoms that are deficient in cyanide ligands; therefore,coordinated water is considered essential for stabilizing TMCCCmaterials. Non-coordinated water above a threshold included in anoptimally selected residual water content would be considered anundesired impurity that degrades the desired electrochemical properties.However, removing all non-coordinated water may result in poor alkalication mobility in the TMCCC material, leading to diminished cell energyavailable for high-power discharge, with only marginal improvement ofcycle or calendar life of the cell. Therefore, in addition tocoordinated water, a certain amount of non-coordinated water is alsonecessary and desired. As discussed herein, absent sufficient care,water management processes (e.g., drying) may not sufficientlydistinguish between coordinated and non-coordinated water in a compoundcoordination material. Coordination compound materials discussed hereinmay be used in a system including a water-containing electrolyte whichmay influence the water content of the coordination compound materialafter assembly or during use. A coordination compound having itsresidual water adjusted to a desired non-degrading water content rangeis referred to herein as a water mediated coordination compoundmaterial. Similarly, a coordination compound having its residual wateroutside this range is referred to herein as a water non-mediatedcoordination compound material.

As used herein, the term “aqueous” in the context of an electrolyte foran electrochemical cell means an electrolyte including water as asolvent and one or more dissolved materials with the water solventhaving a concentration greater than 5%.

As used herein, the term “non-aqueous” in the context of an electrolytefor an electrochemical cell means an electrolyte including a solventother than water, with either no water being present or water having aconcentration less than 5%.

As used herein, the term “anhydrous” in the context of an electrolytefor an electrochemical cell means an electrolyte including a solventother than water, water as a trace impurity having a concentration lessthan 0.01%.

As used herein, the term “drying” in the context of removal of waterfrom a material, refers to removal of water to the greatest degreepossible consistent with the drying process leaving water as a traceimpurity at a concentration limited by the drying process actually used.Drying changes a material to an anhydrous state (therefore a driedmaterial is an anhydrous material).

As used herein, the term “dehydrating” in the context of modifying aconcentration of water in a material, refers to controllably reducingthe water content to a desired level greater than a trace impurity. Incontrast to drying, dehydrating contemplates retaining water asnecessary desirable component of the material, for example, retainingall coordinated water and retaining a certain residual content ofnon-coordinated water.

As used herein, the term “hydrating” in the context of modifying aconcentration of water in a material, refers to controllably increasingthe water content to a desired level greater than a trace impurity,within target ranges needed for optimal performance and calendar life ofan electrochemical cell.

As used herein, the term “mediating” in the context of modifying aconcentration of water content in a coordination compound such as aTMCCC material includes dehydrating or hydrating the material to achievea desired coordinated water concentration that enables the desiredelectrochemical properties. One way to consider water content quantitymediation is consideration of a mass fraction of water of a TMCCCmaterial, including non-coordinated and coordinated water, both beforeand after mediation.

As used herein, a “grade” of a separator may reference an importantcharacteristic such as a thickness, number of laminated layers, and thelike. For a separator including a ceramic component as further describedherein, a grade may refer to a size of individual ceramic particles, arelative thickness of a layer including ceramic elements versus anothernon-ceramic layer of that separator, for example a layer includingpolymer-only components, or other physical characteristic.

In some instances, a grade may refer to chemical attributes such as acomposition of the ceramic. As used herein, the term “ceramic” in thecontext of a separator used in a secondary electrochemical cell includesa class of materials identifying generally by a chemical formula:M_(x)O_(y)H_(z), with x, y, z identifying quantities of a metal (M),oxygen (O), and hydrogen (H). Preferably, M includes at least one ofaluminum or silicon though in other embodiments a ceramic may includeone or more metal oxides including alkaline earth oxides and transitionmetal oxides.

As used herein, a coordination complex includes a central atom or ion,which is usually metallic and is called the coordination center, and asurrounding array of bound molecules or ions, that are in turn known asligands or complexing agents. Many metal-containing compounds,especially those that include transition metals (elements liketitanium), are coordination complexes. A specific type of coordinationcompound, a transition metal cyanide coordination compound identified byA_(x)P_(y)[R(CN)₆]_(z)(H₂O)_(n) wherein wherein A identifies as one ormore alkali cations and P and R each represent one or more divalent ortrivalent transition metal cations; wherein 0.5<z<1; wherein x, y, and zare related based on electrical neutrality, x>0, y>0, z>0; and whereinn=6*(1−z)+m, and wherein n>0; wherein 6*(1−z) identifies as a quantityof lattice bound water and m identifies as a quantity of non-coordinatedwater; wherein m≥0; wherein 0≤x≤2, and y=1.

An embodiment includes an electrochemical cell having a first electrode,a second electrode, a liquid electrolyte disposed in electrochemicalcommunication with the electrodes, and a separator disposed in theliquid electrolyte and between the electrodes, the separator including aceramic composition, wherein one of the electrodes includes acoordination compound.

The general procedure used to fabricate a TMCCC electrochemical cellconsists of several steps and will be outlined in the followingparagraphs. The first step is to fabricate individual electrode sheets.A slurry containing one or more TMCCC active material powders, a smallamount of one or more polymer binder species and a small amount of oneor more carbon additive species is mixed into one or more organicsolvents to produce a homogeneous mixture. The mixture is then cast at aconstant thickness onto an aluminum current collector, resulting in athin coating layer of the slurry on the current collector surface. Theorganic solvent is then driven out of the thin coating layer viaevaporation, resulting in a solid electrode composite adhered to thecurrent collector, with a thickness of less than 200 microns. Theelectrode sheet is then calendered to a desired thickness in order tocontrol the electrode composite porosity. The same general procedure forfabricating electrodes is employed for both anode and cathodeelectrodes. For the following examples, sodium manganese-ironhexacyanoferrate was used as the TMCCC cathode active material andsodium manganese hexacyanomanganate was used as the TMCCC anode activematerial.

The next step is to assemble the electrochemical cell. Anode and cathodeelectrodes are punched into coupons where each coupon has an area ofbare aluminum to serve as the electrical contact to the electrode. Thecell is assembled by first laying down a cathode electrode, then layingdown a commercially available separator onto the cathode electrodecomposite, and then laying down an anode electrode on top of theseparator. This process can be repeated multiple times to create amulti-layer cell stack. The separator area is slightly oversizedcompared to the anode and cathode electrode areas, to ensure properinsulation between electrodes. The stack is taped together around theoutside of the cell stack. Aluminum tabs are welded to the bare aluminumareas on the electrode coupons. The cell stack is then placed into amylar-coated aluminum pouch and the pouch is sealed on three sides,where the aluminum tabs protrude from one edge of the pouch. Anacetonitrile-based electrolyte is then added into the pouch at a volumein slight excess of the cell stack's total pore volume. After allowingthe electrolyte to wet the cell stack, the pouch is vacuum-sealed, thusproducing the fully assembled electrochemical pouch cell. All exampleslisted herein use this general procedure to create one of two types ofcells: a two-layer cell with nominal capacity 24 mAh, or a multi-layercell with nominal capacity 4 Ah. The steps used to produce such a cellfrom the components includes may be performed in other orders, and somesteps may be excluded from the procedure, or some additional processingsteps may be introduced in addition to those described herein.

For each TMCCC material, electrodes were prepared by mixing the activematerial powder with carbon black and either a polyvinylidene difluoridebinder in a solvent of n-methyl pyrrolidinone, or a styrene-butadienecopolymer binder in a solution of butanol and xylenes. The electrodeswere prepared with a mass ratio of 8:1:1 active material powder, carbonblack, and binder. The resulting slurry was spread on a substrate madeof either carbon felt or carbon coated aluminum foil and then dried in avacuum oven at a temperature of approximately 100° C. Variations of thiselectrode preparation process may be used to achieve enhanced electrodeperformance. These variations may include selection of variousconductive carbons or combinations of conductive carbons including butnot limited to carbon black, graphite, or hard carbon, or selection ofvarious binders or combinations of binders including but not limited tovinylfluoride/hexafluoropropylene copolymer, polyvinylidenefluoride(PVDF), polyacrylonitrile, polymethylmethacrylate,polytetrafluoroethylene, or styrene butadiene rubber-based polymer.Variations of this electrode preparation process may also include thetemperature, duration, and pressure during electrode drying.

Each of these TMCCC electrodes may be combined with other counterelectrodes capable of undergoing an electrochemical reaction at higheror lower potential to produce a cell having non-zero voltage. Counterelectrodes may include sodium-ion electrodes such as TMCCC cathodes,layered transition metal oxides such as sodium manganese oxide,transition metal phosphates such as sodium vanadium phosphate, otherceramic electrodes containing electrochemically active transitionmetals, metals capable of alloying with sodium, including tin, antimony,and lead, and carbons including graphitic, hard, or soft carbons.Counter electrodes may also include electrodes that undergo anelectrochemical reaction with a cation different from sodium, such aslithium or potassium, including lithium-ion electrode materialsincluding layered oxides such as lithium cobalt oxide, transition metalphosphates such as lithium iron phosphate, alloys capable of undergoingreactions with lithium, such as silicon, and carbons including graphite.

Each of these TMCCC electrodes may further be combined with otherelectrolyte solvents and electrolyte salts during cell assembly. Otherorganic electrolyte solvents that are electrochemically inactive in theoperating electrochemical potential range of the TMCCC electrode and thecounter electrode may be used in a practical cell. These solventsinclude nitriles such as succinonitrile or propionitrile, carbonatesincluding propylene carbonate or dimethyl carbonate, sulfones includingsulfolane and dimethyl sulfone, sulfoxides including dimethyl sulfoxide,amides including dimethylformamide, ethers including glymes includingdiglyme, triglyme, tetraglyme, 1,4-dioxane, or 1,3-dioxolane, lactonesincluding gamma-valerolactone, glycol ethers including methylene glycolmonoethylether, or other solvents, or a combination thereof. Otherelectrolyte salts that are soluble in the electrolyte solvent and thatare electrochemical inactive in the operating electrochemical potentialrange of the TMCCC electrode and the counter electrode may be used in apractical cell. These salts may include sodium hexafluorophosphate,sodium tetrafluoroborate, sodium perchlorate, sodium(trifluoromethane)sulfonimide, sodium4,5-dicyano-2-(trifluoromethyl)imidazolide, or other sodium salts, or acombination thereof. Furthermore, as the TMCCC electrode or itscounterelectrode may undergo electrochemical reactions with othercations such as lithium, potassium, or magnesium, these salts mayinclude lithium, potassium, or magnesium salts of tetrafluoroborate,perchlorate, (fluoromethane)sulfonimide, (trifluoromethane)sulfonimide,4,5-dicyano-2-(trifluoromethyl)imidazolide, or a combination thereof.Furthermore, these TMCCC electrodes may be operated in aqueouselectrolytes containing water in a concentration greater than thatassociated with impurities, such as 2% or more, or in electrolytesincluding one or more ionic liquids, including but not limited to anionic liquid including (trifluoromethane)sulfonimide.

Described herein is a particular assembled cell in which a particulargrade of separator including a plurality of components has been used toenhance cell performance. This plurality of separator components mayinclude one or more of a polymer component including but not limited toa polyethylene or polypropylene, as well as a ceramic componentincluding but not limited to aluminum oxide, aluminum oxyhydroxide,aluminum hydroxide, silicon dioxide, and oxyhydroxides of silicon, aswell as mixed aluminum-silicon oxides and mixed aluminum-siliconoxyhydroxides. Said ceramic component may further include a transitionmetal oxide or transition metal oxyhydroxide, including but not limitedto those including the same transition metals found in one or both ofthe TMCCC electrodes, or excluding the transition metals found in saidelectrodes. Said ceramic components may include surface groups that arethe same or different from the bulk composition of each ceramic particlecomprising that component. For example, in one instance a ceramiccomponent comprising silicon dioxide may also include surface groupscomprising silicon hydroxide or silicon oxyhydroxide. Said ceramiccomponents may include water, therefore comprising hydrates of oxide,oxyhydroxide, or hydroxide phases. Said ceramic components mayreversibly absorb and release water when dried via processes such asexposure to heat or vacuum. Said ceramic components may alternativelypermanently bind absorbed water.

Said polymer components of said separators may include a particularmolecular weight. Said polymer components may include a particularporosity comprising a plurality of pores of a particular size, such asless than 10 nanometers, 10-100 nanometers, or 100-1000 nanometers. Saidpolymer components may include a plurality of polymers blended togetherinto a homogeneous or quasi-homogeneous medium, or may form discreteregions such as discrete layers, each of which may contain one or moreof said polymers.

Said ceramic components of said separators may include a particularparticle size distribution, such as 10 nanometers, 10-100 nanometers,100-1000 nanometers, or greater than 1000 nanometers. In some instances,said ceramic components may include particles of multiple sizes, such asparticles including sizes in the range of 10-100 nanometers andparticles including sizes in the range of greater than 1000 nanometers.Said ceramic particles may be distributed homogeneously orquasi-homogeneously with said polymer components. Said ceramic particlesmay also form a layer that excludes any polymer components or thatincludes only a small amount of polymer components, such as 20% or less.Said ceramic particle layers may comprise a multi-layer separator inwhich a ceramic particle layer is adjacent to a layer containing onlypolymer components. Furthermore, a separator containing such layers mayinclude three or more layers, each of which may contain only polymercomponents, primarily ceramic particles excluding polymer components orincluding only a small amount of polymer components, or both polymer andceramic components distributed homogeneously or quasi-homogeneously insaid layer. In one instance, a separator may contain a single layercontaining a homogeneous distribution of polymer components and ceramicparticles. In another instance, a separator may contain a first layercomprising only polymer components, and a second layer comprisingprimarily ceramic particles and a small quantity of ceramic components.In another instance, a separator may contain three layers, with a middlelayer comprising only polymer components, and two adjacent layerscomprising primarily ceramic particles and a small quantity of ceramiccomponents.

The performance of the battery cell may depend on physical properties ofthe separator, including but not limited to density, thickness, porosity(percent of total volume comprised by pore volume), pore tortuosity,pore size, and the areal density of pores. The performance of thebattery cell may further depend on chemical properties of the separator,including but not limited to its composition, whether or not it containsparticular species of polymer components or ceramic components. Theperformance of the battery cell may further depend on chemical reactionsthat may occur between the separator and other chemical species in thecell, including but not limited to water that may be present in thecell, said water initially present in the electrolyte, one or more ofthe electrodes, or another cell component. Said chemical reactionsbetween the separator and water may include absorption of water. Saidabsorption may be reversible or irreversible. The amount of waterabsorbed via said chemical reactions may scale proportionally with themass, surface area, or another quantity representing an amount ofceramic component included in said separator.

An embodiment of the instant invention is a cell containing a separatorcontaining a ceramic component comprising at least 50% of the total massof the separator. Another embodiment of this invention is a cellcontaining a separator containing a ceramic component having a mass ofat least 1 g per square meter, and up to about 25 g per square meter ormore. Another embodiment of the instant invention is a cell containing aseparator containing a ceramic component comprising at least 30% of thetotal volume of the separator, up to about 60% of the total volume ofthe separator, or more. Another embodiment of the instant invention is acell containing a separator containing a ceramic component an a polymercomponent and having a total thickness of at least 5 microns, or atleast 10 microns, or at least 25 microns, or at least 50 microns.

The general procedure used to test the electrochemical performance ofthe cell consists of continuous cycles of constant-current charging anddischarging the cell at a current per limiting electrode active materialmass of 66 mA/g. The rate of cell capacity loss describes theelectrochemical cell's lifetime performance, where a lower rate ofcapacity loss is desired. To increase the pace of learning, cells aretested under increased stress conditions including constant voltageholds at the maximum cell voltage and testing at elevated ambienttemperature of 55° C. A typical voltage profile for a singlecharge-discharge cycle at ambient temperature 55° C. is shown in FIG. 3.

Examples

Example 1. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#1 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 2. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#2 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 3. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#3 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 4. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#4 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 5. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#5 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 6. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#6 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 7. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#7 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 8. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#8 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 9. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a multi-layer cellwith nominal capacity 4 Ah. During cell assembly, a separator of grade#8 having properties as listed in table 1 was used. The rest of the cellfabrication steps were the same as described in the general procedure.The general testing procedure already described was used to assess thelifetime performance of a cell with this composition.

Example 10. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#10 having properties as listed in table 1 was used. The rest of thecell fabrication steps were the same as described in the generalprocedure. The general testing procedure already described was used toassess the lifetime performance of a cell with this composition.

Example 11. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#11 having properties as listed in table 1 was used. The rest of thecell fabrication steps were the same as described in the generalprocedure. The general testing procedure already described was used toassess the lifetime performance of a cell with this composition.

Example 12. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#12 having properties as listed in table 1 was used. The rest of thecell fabrication steps were the same as described in the generalprocedure. The general testing procedure already described was used toassess the lifetime performance of a cell with this composition.

Example 13. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#13 having properties as listed in table 1 was used. The rest of thecell fabrication steps were the same as described in the generalprocedure. The general testing procedure already described was used toassess the lifetime performance of a cell with this composition.

Example 14. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#14 having properties as listed in table 1 was used. The rest of thecell fabrication steps were the same as described in the generalprocedure. The general testing procedure already described was used toassess the lifetime performance of a cell with this composition.

Example 15. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 24 mAh. During cell assembly, a separator of grade#15 having properties as listed in table 1 was used. The rest of thecell fabrication steps were the same as described in the generalprocedure. The general testing procedure already described was used toassess the lifetime performance of a cell with this composition.

Example 16. A set of electrochemical cells was fabricated using thegeneral fabrication procedure already described for a two-layer cellwith nominal capacity 4 Ah. During cell assembly, a separator of grade#16 having properties as listed in table 1 was used. The rest of thecell fabrication steps were the same as described in the generalprocedure. The general testing procedure already described was used toassess the lifetime performance of a cell with this composition.

Table I includes key separator properties of separator grades employedin the examples herein. Base film materials include polyethylene (PE),polypropylene (PP), and/or a tri-layer of polypropylene, polyethylene,and polypropylene (PP/PE/PP).

TABLE I Outlined Separator Properties Sepa- Base Cera- Cera- Total ratorBase film Cera- mic mic thick- grade film porosity mic particle loadingness # material [%] species size [g/m2] [um] 1 PE 44 — — 0.0 20.0 2 PE44 Al₂O₃ nano 9.0 22.0 3 PE 44 AlOOH micro 8.2 22.0 4 PE 44 SiO₂ nano5.3 22.0 5 PE 49 — — 0.0 20.0 6 PE 49 Al₂O₃ nano 2.6 22.0 7 PE 49 Al₂O₃nano 6.2 20.0 8 PE 49 Al₂O₃ nano 9.0 22.0 9 PE 55 — — 0.0 12.0 10 PE 55— — 0.0 20.0 11 PE 55 Al₂O₃ nano 5.5 16.0 12 PP 52 — — 0.0 12.0 13PP/PE/PP 45 — — 0.0 14.0 14 PP/PE/PP 45 Al₂O₃ micro 7.0 18.0 15 PP/PE/PP50 Al₂O₃ micro 7.0 22.5

FIG. 1 illustrates a scanning electron microscopy (SEM) image of awet-processed polyethylene (PE) separator surface, and FIG. 2illustrates an SEM image of a dry-processed polypropylene (PP) separatorsurface.

FIG. 3 illustrates an SEM image of a surface of a first alumina-coatedseparator wherein alumina particles are of a micron size scale (microscale), FIG. 4 illustrates an SEM image of a surface of a secondalumina-coated separator wherein alumina particles are of a nano sizescale (nano scale).

FIG. 5 illustrates a constant-current charge-discharge voltage profileat a current per limiting electrode active material mass of 66 mA/g, atan ambient temperature of 55° C., of a cell containing a sodiummanganese iron hexacyanoferrate cathode, a sodium manganesehexacyanomanganate anode, and acetonitrile-based electrolyte, withseparator grades #11, 13, 14 described in Table 1.

FIG. 6 illustrates a lifetime effect of base film porosity including PEseparators with constant total thicknesses exhibit monotonicallyimproving lifetime performance with lower porosity.

FIG. 7 illustrates a lifetime effect of ceramic coating wherein uncoatedPP, PE, and PP/PE/PP separators exhibit inferior performance compared toalumina-coated PE and alumina-coated PP/PE/PP. Note that there may existother differences between the alumina-coated separators and uncoatedseparators, such as base film porosities and total thicknesses, howeverthe effect of the alumina-coatings is expected to outweigh the effectsof these differences.

FIG. 8 illustrates a lifetime effect of ceramic loading wherein PEseparators with constant base film porosities and total thicknessesexhibit monotonically improving lifetime performance with increasingAl₂O₃ mass loading.

FIG. 9 illustrates a lifetime effect of ceramic species whereinAl₂O₃-coated PE exhibits superior performance to AlOOH-coated PE, andboth are superior to SiO₂-coated PE. All ceramic species are coated ontobase films of identical compositions. Note that ceramic mass loadingsbetween these separator grades differ due to different densities of theceramic species. However, the effect of ceramic species is expected tooutweigh the effect of mass loadings.

FIG. 10 illustrates a lifetime effect of ceramic particle size whereinseparators coated with nano-Al₂O₃ particles exhibit superior lifetimeperformance when compared to separators coated with micro-Al₂O₃particles. Note that there may exist other differences between these twogrades, such as base film materials and ceramic mass loadings, but theeffect of the Al₂O₃ particle size is expected to outweigh the effects ofthese differences.

FIG. 11 illustrates a generic electrochemical cell 1100. Cell 1100includes a first electrode 1105 (e.g., a cathode electrode), a secondelectrode 1110 (e.g., an anode electrode), a liquid electrolyte 1115, aseparator 1120, a first current collector 1125, and a second currentcollector 1130. One or both of the electrodes includes a coordinationcompound, and more specifically a transition metal cyanide coordinationcompound. Separator 1120 includes a set of ceramics characteristics asfurther set forth herein.

Electrode 1105 and electrode 1110 are electrochemically communicatedwith liquid electrolyte 1115. Separator 1120 is disposed between theelectrodes and within liquid electrolyte 1115.

The system and methods above have been described in general terms as anaid to understanding details of preferred embodiments of the presentinvention. In the description herein, numerous specific details areprovided, such as examples of components and/or methods, to provide athorough understanding of embodiments of the present invention. Somefeatures and benefits of the present invention are realized in suchmodes and are not required in every case. One skilled in the relevantart will recognize, however, that an embodiment of the invention can bepracticed without one or more of the specific details, or with otherapparatus, systems, assemblies, methods, components, materials, parts,and/or the like. In other instances, well-known structures, materials,or operations are not specifically shown or described in detail to avoidobscuring aspects of embodiments of the present invention.

Reference throughout this specification to “one embodiment”, “anembodiment”, or “a specific embodiment” means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention and notnecessarily in all embodiments. Thus, respective appearances of thephrases “in one embodiment”, “in an embodiment”, or “in a specificembodiment” in various places throughout this specification are notnecessarily referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics of any specificembodiment of the present invention may be combined in any suitablemanner with one or more other embodiments. It is to be understood thatother variations and modifications of the embodiments of the presentinvention described and illustrated herein are possible in light of theteachings herein and are to be considered as part of the spirit andscope of the present invention.

It will also be appreciated that one or more of the elements depicted inthe drawings/figures can also be implemented in a more separated orintegrated manner, or even removed or rendered as inoperable in certaincases, as is useful in accordance with a particular application.

Additionally, any signal arrows in the drawings/Figures should beconsidered only as exemplary, and not limiting, unless otherwisespecifically noted. Combinations of components or steps will also beconsidered as being noted, where terminology is foreseen as renderingthe ability to separate or combine is unclear.

The foregoing description of illustrated embodiments of the presentinvention, including what is described in the Abstract, is not intendedto be exhaustive or to limit the invention to the precise formsdisclosed herein. While specific embodiments of, and examples for, theinvention are described herein for illustrative purposes only, variousequivalent modifications are possible within the spirit and scope of thepresent invention, as those skilled in the relevant art will recognizeand appreciate. As indicated, these modifications may be made to thepresent invention in light of the foregoing description of illustratedembodiments of the present invention and are to be included within thespirit and scope of the present invention.

Thus, while the present invention has been described herein withreference to particular embodiments thereof, a latitude of modification,various changes and substitutions are intended in the foregoingdisclosures, and it will be appreciated that in some instances somefeatures of embodiments of the invention will be employed without acorresponding use of other features without departing from the scope andspirit of the invention as set forth. Therefore, many modifications maybe made to adapt a particular situation or material to the essentialscope and spirit of the present invention. It is intended that theinvention is not limited to the particular terms used in followingclaims and/or to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include any and all embodiments and equivalents falling within thescope of the appended claims. Thus, the scope of the invention is to bedetermined solely by the appended claims.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. An electrochemical cell, comprising: a firstelectrode; a second electrode; a liquid electrolyte disposed inelectrochemical communication with said electrodes; and a separatordisposed in said liquid electrolyte and between said electrodes, saidseparator including a ceramic composition; wherein one of saidelectrodes includes a coordination compound; and wherein saidcoordination compound includes d identifying as a quantity ofnon-coordinated water; wherein d>0.
 2. The electrochemical cell of claim1 wherein said ceramic composition includes a material identifying asM_(x)O_(y)H_(z), with x, y, z identifying quantities of a metal (M),oxygen (O), and hydrogen (H); wherein x≥1; wherein y≥x+z/2 and y≤3x+z/2;and wherein z>0 and z≤y.
 3. The electrochemical cell of claim 2 whereinM includes at least one of aluminum or silicon.
 4. The electrochemicalcell of claim 1 wherein said coordination compound includes a transitionmetal cyanide coordination compound identified by Formula I, byA_(a)P_(b)[R(CN)₆]_(c)(H₂O)_(n) wherein A identifies as one or morealkali cations and P and R each represent one or more divalent ortrivalent transition metal cations; wherein 0.5<c<1; wherein a, b, and care related based on electrical neutrality, a>0, b>0, c>0; and whereinn=6*(1−z)+d, and wherein n>0; wherein 6*(1−z) identifies as a quantityof lattice bound water; wherein 0≤a≤2, and b=1.
 5. The electrochemicalcell of claim 2 wherein said coordination compound includes a transitionmetal cyanide coordination compound identified by Formula I, byA_(a)P_(b)[R(CN)₆]_(c)(H₂O)_(n) wherein A identifies as one or morealkali cations and P and R each represent one or more divalent ortrivalent transition metal cations; wherein 0.5<c<1; wherein a, b, and care related based on electrical neutrality, a>0, b>0, c>0; and whereinn=6*(1−z)+d, and wherein n>0; wherein 6*(1−z) identifies as a quantityof lattice bound water; wherein 0≤a≤2, and b=1.
 6. The electrochemicalcell of claim 3 wherein said coordination compound includes a transitionmetal cyanide coordination compound identified by Formula I, byA_(a)P_(b)[R(CN)₆]_(c)(H₂O)_(n) wherein A identifies as one or morealkali cations and P and R each represent one or more divalent ortrivalent transition metal cations; wherein 0.5<c<1; wherein a, b, and care related based on electrical neutrality, a>0, b>0, c>0; and whereinn=6*(1−z)+d, and wherein n>0; wherein 6*(1−z) identifies as a quantityof lattice bound water; wherein 0≤a≤2, and b=1.
 7. The electrochemicalcell of claim 1 wherein said ceramic composition includes particleshaving sizes <100 nm.
 8. The electrochemical cell of claim 1 whereinsaid separator includes two or more discrete layers, including a firstlayer consisting essentially of one or more polymers, and a second layerconsisting essentially of a ceramic composition.
 9. An electrochemicalcell, comprising: a first electrode; a second electrode; a liquidelectrolyte disposed in electrochemical communication with saidelectrodes; and a separator disposed in said liquid electrolyte andbetween said electrodes, said separator including a multilayerconstruction; wherein one of said electrodes includes a coordinationcompound; and wherein said coordination compound includes d identifyingas a quantity of non-coordinated water; wherein d>0.
 10. Theelectrochemical cell of claim 9 wherein said coordination compoundincludes a transition metal cyanide coordination compound identified byFormula I, by A_(a)P_(b)[R(CN)₆]_(c)(H₂O)_(n) wherein A identifies asone or more alkali cations and P and R each represent one or moredivalent or trivalent transition metal cations; wherein 0.5<c<1; whereina, b, and c are related based on electrical neutrality, a>0, b>0, c>0;and wherein n=6*(1−z)+d, and wherein n>0; wherein 6*(1−z) identifies asa quantity of lattice bound; wherein 0≤a≤2, and b=1.
 11. Theelectrochemical cell of claim 9 wherein said multilayer constructionincludes particles having sizes <100 nm.
 12. The electrochemical cell ofclaim 9 wherein said separator includes two or more discrete layers,including a first layer consisting essentially of one or more polymers,and a second layer consisting essentially of a ceramic composition. 13.A method for manufacturing an electrochemical cell, comprising:producing a first electrode including a coordination compound; producinga second electrode; producing a liquid electrolyte; producing aseparator, said separator including a ceramic composition; andassembling the electrochemical cell including electrochemicallycommunicating said electrodes to said liquid electrolyte and disposingsaid separator between said electrodes; wherein said coordinationcompound includes d identifying as a quantity of non-coordinated water;wherein d>0.
 14. The method of claim 13 wherein said ceramic compositionincludes a material identifying as M_(x)O_(y)H_(z), with x, y, zidentifying quantities of a metal (M), oxygen (O), and hydrogen (H);wherein x≥1; wherein y≥x+z/2 and y≤3x+z/2; and wherein z≥0 and z≤y. 15.The method of claim 13 wherein said coordination compound includes atransition metal cyanide coordination compound identified by Formula I,by A_(a)P_(b)[R(CN)₆]_(c)(H₂O)_(n) wherein A identifies as one or morealkali cations and P and R each represent one or more divalent ortrivalent transition metal cations; wherein 0.5<c<1; wherein a, b, and care related based on electrical neutrality, a>0, b>0, c>0; and whereinn=6*(1−z)+d, and wherein n>0; wherein 6*(1−z) identifies as a quantityof lattice bound water; wherein 0≤a≤2, and b=1.
 16. The method of claim13 wherein said separator includes two or more discrete layers,including a first layer consisting essentially of one or more polymers,and a second layer consisting essentially of a ceramic composition. 17.A method for manufacturing an electrochemical cell, comprising:producing a first electrode including a coordination compound; producinga second electrode; producing a liquid electrolyte; producing aseparator, said separator including a discrete multilayer composition;and assembling the electrochemical cell including electrochemicallycommunicating said electrodes to said liquid electrolyte and disposingsaid separator between said electrodes; and wherein said coordinationcompound includes d identifying as a quantity of non-coordinated water;wherein d>0.
 18. The method of claim 17 wherein said multilayerconstruction includes a material identifying as M_(x)O_(y)H_(z), with x,y, z identifying quantities of a metal (M), oxygen (O), and hydrogen(H)); wherein x≥1; wherein y≥x+z/2 and y≤3x+z/2; and wherein z≥0 andz≤y.
 19. The method of claim 17 wherein said coordination compoundincludes a transition metal cyanide coordination compound identified byFormula I, by A_(a)P_(b)[R(CN)₆]_(c)(H₂O)_(n) wherein A identifies asone or more alkali cations and P and R each represent one or moredivalent or trivalent transition metal cations; wherein 0.5<c<1; whereina, b, and c are related based on electrical neutrality, a>0, b>0, c>0;and wherein n=6*(1−z)+d, and wherein n>0; wherein 6*(1−z) identifies asa quantity of lattice bound water; wherein 0≤a≤2, and b=1
 20. The methodof claim 17 wherein said separator includes two or more discrete layers,including a first layer consisting essentially of one or more polymers,and a second layer consisting essentially of a ceramic composition. 21.The electrochemical cell of claim 1 wherein said separator is configuredto include a mass loading greater than 1 gram per square meter of theceramic composition.
 22. The electrochemical cell of claim 9 whereinsaid separator is configured to include a mass loading greater than 1gram per square meter of a ceramic composition.
 23. The method of claim11 wherein said separator is configured to include a mass loadinggreater than 1 gram per square meter of the ceramic composition.
 24. Themethod of claim 13 wherein said separator is configured to include amass loading greater than 1 gram per square meter of a ceramiccomposition.